The control and monitoring of automated processes in the chemical, pharmaceutical, process, and other industries is increasingly being effected from control rooms, to which large amounts of process data generated within the respective plant are transmitted, e.e., via field buses.
To generate such process data, use is commonly made of a large number of field devices installed at or in the immediate vicinity of the process, such as measuring instruments, control equipment, and/or data storage devices, which can supply the corresponding measured and/or control variables in the form of standardized analog or digital signals.
In spite of the fact that the interpretation of process data is nowadays performed essentially with the aid of computers, particularly remote from the field, operative on-site monitoiing, i.e., monitoring by operating personnel in the plant, is often necessary and usually prescribed. Therefore, such process data generated in the field will continue to be visualized not only in control. rooms but also directly at the field devices providing these process data, particularly in fully automated plants.
For the on-site visualization of individual process data, different types of display elements, such as bar-graph or digital displays, particularly liquid crystal displays, have proved effective. Also, display elements of the kind known from pointer instruments are still being widely used. Aside from the on-site visualization of the measured variable proper, commercially available field devices often provide for on-site visualization of selected field device data, such as device error messages or parameters representing current device configurations.
A problem associated with such on-site operative monitoring is that, on the one hand, the process data necessary in the increasingly complex plants for the description of the conditions to be monitored are increasing in volume, while, on the other hand, an interpretation of the process data in the sense of an assignment to one of the conditions to be monitored can be performed “manually” by operators on site only for process data sets of small volume.
Aside from the fact that such process data sets are frequently much too large for comprehensive on-site operative monitoring, fast, particularly simultaneous, visual perception of the relevant data by operating personnel is often not possible since the respective field devices and, thus, their display elements are generally far apart, so that they cannot be viewed simultaneously.